The re­stric­tions will in­voke au­thor­i­ties used by Pres­i­dent Don­ald Trump to im­ple­ment his “travel ban” in early 2017, ac­cord­ing to se­nior ad­min­is­tra­tion of­fi­cials who out­lined them, and ap­ply in­def­i­nitely.

The mea­sures are ex­pected to face swift le­gal chal­lenges. Im­mi­grant ad­vo­cacy groups in­sist that U.S. laws clearly ex­tend asy­lum pro­tec­tions to any­one who reaches the United States and ex­presses a fear of per­se­cu­tion, no mat­ter how they en­ter the coun­try.

Ad­min­is­tra­tion of­fi­cials said the Supreme Court has up­held the pres­i­dent’s broad ex­ec­u­tive pow­ers on such mat­ters and that the re­stric­tions rolled out Thurs­day rep­re­sent a rea­son­able re­sponse as the na­tion’s im­mi­gra­tion sys­tem is drown­ing in what they char­ac­ter­ized as friv­o­lous asy­lum claims by mi­grants who cross il­le­gally.

“Those who en­ter the coun­try be­tween (of­fi­cial) ports of en­try – i.e. il­le­gally – are know­ingly and vol­un­tar­ily break­ing the law,” one ad­min­is­tra­tion of­fi­cial said. “So it’s just im­por­tant to re­mind every­body that while all im­mi­gra­tion laws do af­ford peo­ple var­i­ous forms of pro­tec­tion, the re­al­ity is that it’s a vi­o­la­tion of fed­eral law to en­ter our coun­try in the man­ner that th­ese il­le­gal aliens are en­ter­ing the coun­try.”

Trump is pre­par­ing to is­sue a procla­ma­tion as­sert­ing the emer­gency pow­ers, and the rule changes will be pub­lished Fri­day in the Fed­eral Reg­is­ter, ac­cord­ing to the of­fi­cials, who spoke with the me­dia in a con­fer­ence call on the con­di­tion of anonymity. They did not ex­plain why they could not be iden­ti­fied.

Th­ese asy­lum re­stric­tions mark the ad­min­is­tra­tion’s lat­est at­tempt to pre­vent im­mi­grants and for­eign­ers from en­ter­ing the United States. Thurs­day’s an­nounce­ment comes as an es­ti­mated 7,000 to 10,000 Cen­tral Amer­i­cans move north through Mex­ico in car­a­van groups. Trump has de­manded new tools to stop them from en­ter­ing the United States and or­dered the de­ploy­ment of thou­sands of the U.S. troops to back up bor­der agents.

“Our na­tion is ex­pe­ri­enc­ing an un­prece­dented cri­sis on our South­ern Bor­der,” the Depart­ment of Home­land Se­cu­rity said in a state­ment. “Low stan­dards for claim­ing a fear of per­se­cu­tion have al­lowed aliens with mer­it­less claims to il­le­gally en­ter our coun­try, claim “cred­i­ble fear,” and then in many cases be re­leased pend­ing lengthy pro­ceed­ings.”

Pri­vately, Home­land Se­cu­rity of­fi­cials ac­knowl­edge the new mea­sures, at least on their own, are un­likely to achieve the kind of im­me­di­ate de­ter­rent ef­fect the White House de­sires.

De­ten­tion ca­pac­ity at U.S. im­mi­gra­tion jails is nearly maxed out, and court-im­posed lim­its on the gov­ern­ment’s abil­ity to hold chil­dren in im­mi­gra­tion jails mean car­a­van fam­i­lies who seek pro­tec­tion are still likely to be re­leased into the United States pend­ing a hear­ing.

“Congress very specif­i­cally said you can ap­ply for asy­lum if you ar­rive in the United States re­gard­less of whether you’re at a port of en­try,” said Omar Jad­wat, di­rec­tor of the Amer­i­can Civil Lib­er­ties Union’s Im­mi­grants’ Rights Project. “They clearly and ex­plic­itly meant to make asy­lum avail­able to any­one who reaches the United States.